New Microscope Shows Neutron Pattern, Promise

Author:  Jessica Tanenbaum
Institution:  Yale University
Date:  July 2004

Adelphi Technology has reported a new neutron microscope prototype in Applied Physics Letters. With a 0.5 millimeter resolution--about half the thickness of a dime--and a 10x magnification capability, the microscope still needs tinkering, but eventually, Adelphi may achieve better image resolution with the neutrons’ single nanometer (nm) wavelength than with visible light, which has wavelengths between 400 and 700 nm.

Ted Cremer, an Adelphi scientist, explained that while a camera could capture a suitcase and an airport scanner could capture a metal gun inside of a suitcase, a neutron imaging process could see the hydrogen-rich explosive material of the bullets.

"Neutrons can penetrate right down to the nucleus, so they image portions of an object that would otherwise not be seen by other modalities," explained Cremer.

Cremer and other scientists from Adelphi, based in San Carlos, California, traveled to the Center for Neutron Research at the National Institute of Standards and Measures (NIST) in Gaithersburg, Maryland on April, 2003 and January, 2004 to use NIST’s cold neutron source technology.

Created with support from NIST, Adelphi, and Stanford, the microscope bombards a biological sample with high-speed neutrons. Unlike with other imaging techniques that involve slicing or staining samples, Adelphi’s process of neutron microscopy leaves the sample unscathed. The neutrons pierce through the sample in a pattern that reflects its internal structure. Then the neutrons whiz through 100 dimpled aluminum plates, focusing the neutrons for projection onto a detector.

Cremer said Adelphi plans more experiments at NIST with cold neutron imaging in the next year. He is also interested in thermal neutron imaging because thermal neutrons are easier to make in large quantities. Eventually, Adelphi would like to improve resolution and produce a portable neutron microscope for use in the laboratory. "We’re in the infancy of it," said Cremer.